We plan to produce repetitive seizures in large and small animals as a model for status epilepticus in man. Generalized seizures will be produced by supramaximal electroshock and by Indoklon inhalation. Focal seizures will be induced by local application of penicillin to the cerebral cortex. Biochemical alterations in brain tissue (redox potential, high energy phosphates, acid-base status) will be correlated in time and degree with changes in cerebral blood flow during seizures in order to gain insight into the role of tissue factors in the regulation of cerebral blood flow in epilepsy. Whole brain and hemispheric blood flow will be estimated by the venous outflow technique (whole brain) and by injection of radiolabeled microspheres. ATPase activity will be determined on five cortical layers using quantitative histochemical methods in the discharging focus and on the contralateral "control" hemisphere. Pathological changes will be sought for and correlated with biochemical differences when noted. Our goal is to develop an animal model relevant to human status epilepticus in order to determine: 1) if mortality in status epilepticus is a preventible cardio-pulmonary problem, 2) if cerebral anoxia is an inherent result of status epilepticus or merely a consequence of systemic hypoxemia, 3) if vascular factors play a role in generating brain injury in status epilepticus.